Javascript Array includes(searchElement, fromIndex = 0)

Array.prototype.includes = function(searchElement, fromIndex = 0) {
 let arr = this;/* w w  w . j av a2 s.  c  o m*/
 let result = false;
 let start = Math.max(fromIndex < 0 ? fromIndex + arr.length : fromIndex, 0);
 for (let i = start, len = arr.length; i < len; i++) {
  if (arr[i] === searchElement) {
   result = true;
   break;
  }
 }
 return result;
}